The 상어 이빨 (Sang-eo Ippal) or Shark Tooth Class is a nuclear-powered submarine developed by the North Korean Navy, based on a late-1980s Soviet design. This design was modernized and adapted to meet North Korea’s strategic needs. The existence of the Sang-eo class came as a significant surprise to Western intelligence agencies, as the design transfer was a lesser-known component of a clandestine arms deal between North Korea and the Russian government. In exchange for military aid, North Korea gained access to advanced submarine technology. To fund the program, the (NKSD) agency sought external financing with South African nations and the Iranian government. Ultimately, 12 Sang-eo-class submarines were built: three for North Korea, six for South Africa, and three for Iran.

The Sang-eo is equipped with six 530mm torpedo tubes and 32 vertical launch system (VLS) cells, enabling it to carry a mix of torpedoes, cruise missiles, or other payloads. Internally, it has storage for up to 30 torpedoes.